Finally, those great white sharks right off our coast. Abc's linsey davis with how we can all track them. Reporter: Meet mary lee. The 16-foot long, 3,500-pound great white tagged and released just off the coast of cape cod. Oh, yeah, mary lee! Reporter: And this is chris fisher, who is responsible for putting sharks on the map. Literally. Watch as his team attaches a gps satellite tracking device to this great white. Now, each month, more than a million people are logging on to check up on the whereabouts of the nearly 40 sharks he's tagged. New yorkers don't tend to think about sharks -- Reporter: See this little orange dot? That's mary lee. In just the past six months, she's hugged the shoreline from massachusetts to jacksonville, florida. I had to call the authorities in jacksonville beach, because mary lee -- Reporter: Got too close? Look at this. She was within 200 yards of a surf spot in a public peer. Reporter: Are sharks coming closer than they used to? Nobody knows what they used to do. This is the first time we're establishing these tracks to undehat normal even is. Reporter: Fisher hopes his groundbreakinger are search will move people to protect these massive predators, and replace people's fear with curiosity. Linsey davis, abc news, new york.

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